坦克炮控系统摩擦扰动补偿研究

针对坦克水平向炮控伺服系统中存在的摩擦不确定因素及未建模动态,首先建立水平向炮控伺服系统的数学模型,将摩擦扰动和未建模动态视为一个综合扰动项,然后利用扩张状态观测器对综合扰动项进行观测和补偿,并将扩张状态观测器(ESO)补偿回路作为经典PID控制方法的内回路,实现ESO-PID的复合控制;最后对所用方法进行仿真,结果表明,在原有控制方法的基础上设计控制器,集合了PID控制算法的"被动抗扰"和自抗扰控制方法中扩张状态观测器的"主动抗扰"特性,能够在保持控制系统原有特性的基础上大幅度提高炮控系统的稳定精度以及低速性能。     

Analysis and control of general logical networks – An algebraic approach

Since Boolean network is a powerful tool in describing the genetic regulatory networks, accompanying the development of systems biology, the analysis and control of Boolean networks have attracted much attention from biologists, physicists, and systems scientists. From mathematical point of view, the dynamics of a Boolean (control) network is a discrete-time logical dynamic process. This paper surveys a recently developed technique, called the algebraic approach, based on semi-tensor product. The new technique can deal with not only Boolean networks, which allow each node to take two values, but also k-valued networks, which allow each node to take k different values, and mix-valued networks, which allow nodes to take different numbers of values.The paper provides a comprehensive introduction to the new technique, including (1) mathematical background of this new technique – semi-tensor product of matrices and the matrix expression of logic; (2) dynamic models of Boolean networks, and general (multi- or mix-valued) logical networks; (3) the topological structure of Boolean networks and general networks; (4) the basic control problems of Boolean/general control networks, which include the controllability, observability, realization, stability and stabilization, disturbance decoupling, identification and optimization, etc.; (5) some other related applications.     

Network traffic classification via HMM under the guidance of syntactic structure

Network traffic classification is the basis of many network technologies including intrusion detection, traffic scheduling, and quality of service. Given the limitations of existing classification approaches based on the port number, the packet-payload and statistical characteristics of network traffic, in this paper we propose a novel classification method via a hidden Markov model. With the analysis about the time series characteristics and statistical properties of network traffic, we use a hidden Markov model to model for a type of traffic under the guidance of syntactic structure of it. And then a classification approach is presented based on the model. Experiment results on several typical network applications indicate that the combination of time series characteristics and the statistical properties not only make the established model more precise, but also improve the accuracy of network traffic classification.     

Learning-enhanced differential evolution for numerical optimization

Differential evolution (DE) is a simple and powerful population-based search algorithm, successfully used in various scientific and engineering fields. However, DE is not free from the problems of stagnation and premature convergence. Hence, designing more effective search strategies to enhance the performance of DE is one of the most salient and active topics. This paper proposes a new method, called learning-enhanced DE (LeDE) that promotes individuals to exchange information systematically. Distinct from the existing DE variants, LeDE adopts a novel learning strategy, namely clustering-based learning strategy (CLS). In CLS, there are two levels of learning strategies, intra-cluster learning strategy and inter-cluster learning strategy. They are adopted for exchanging information within the same cluster and between different clusters, respectively. Experimental studies over 23 benchmark functions show that LeDE significantly outperforms the conventional DE. Compared with other clustering-based DE algorithms, LeDE can obtain better solutions. In addition, LeDE is also shown to be significantly better than or at least comparable to several state-of-art DE variants as well as some other evolutionary algorithms.     

Surface characterization of 6H-SiC (0001) substrates in indentation and abrasive machining

Surface characterization of 6H-SiC (0001) substrates in indentation and abrasive machining was carried out to investigate microfracture, residual damage, and surface roughness associated with material removal and surface generation. Brittle versus plastic deformation was studied using Vickers indention and nano-indentation. To characterize the abrasive machining response, the 6H-SiC (0001) substrates were ground using diamond wheels with grit sizes of 25, 15 and 7 μm, and then polished with diamond suspensions of 3 and 0.05 μm. It is found that in indentation, there was a scale effect for brittle versus plastic deformation in 6H-SiC substrates. Also, in grinding, the scales of fracture and surface roughness of the substrates decreased with a decrease in diamond grit size. However, in polishing, a reduction in grit size of diamond suspensions gave no significant improvement in surface roughness. Furthermore, the results showed that fracture-free 6H-SiC (0001) surfaces were generated in polishing with the existence of the residual crystal defects, which were associated with the origin of defects in single crystal growth.     

面向电网侧、新能源侧及用户侧的储能容量配置方法研究

电网中普遍存在负荷率过高,电网峰谷差较大的情况.随着风电、光伏等新能源的不断接入,其出力的波动性使得电网调峰问题更加严峻.储能因其具有响应快速、双向调节等优势,在缓解重负载、削峰填谷、平抑新能源波动、提高供电可靠性等方面可发挥关键作用.本文针对电网侧,提出了用于变电站降载及削峰填谷的储能容量配置方法;针对新能源侧,提出了用于平抑新能源出力波动的储能容量配置方法;针对用户侧,提出了用于提高供电可靠性的储能容量配置方法.最后,以某地区电网的实际数据进行了示例分析.     

基于电-热场耦合的35kV电缆中间接头气隙缺陷仿真分析

为了研究电缆接头在不同尺寸空气楔形间隙下的运行性能,本文采用有限元计算方法,设计35kV电缆接头精细化模型,计算电缆接头在发生单相短路故障时的电场和温度分布.结果表明,电缆接头内的空气间隙电场强度集中,绝缘层存在劣化隐患.随着空气间隙长度的增加,气隙内最大电场强度逐渐增大;随着空气间隙深度的增大,气隙内最大电场强度呈先减小后增大的变化规律;气隙内热量的积聚会进一步造成绝缘层的老化.最后,根据现场实际缺陷案例,提出风险预控和防治措施.     

Study on heat conduction and adsorption/desorption characteristic of MIL-101/few layer graphene composite

Journal of Porous Materials - Aiming at the poor heat conduction performance of porous MIL-101 applied in adsorption cooling process, few layer graphene (FLG) was selected as a promising thermal...     

致密油藏直井多层缝网压裂产量递减分析

垂向多层发育的致密油藏常采用缝网压裂进行开采,从而改善储层渗透率,提高油井产量。为此建立直井多层缝网压裂不稳定渗流数学模型,压裂后各层划分为人工裂缝区、改造区和未改造区。绘制分析Blasingame产量递减典型曲线,曲线分为7个流动阶段,总裂缝长度一定时,裂缝半长短的储层流体渗流率先到达未改造区,流体渗流阻力大,Blasingame曲线靠下;总改造体积一定时,各层改造体积差异越大,Blasingame曲线越靠下。用所建立的模型,对实测生产资料进行解释,获得各层裂缝半长、改造区渗透率等相关地层参数,该模型对进行多层缝网压裂直井产量分析具有指导意义。     

花斑无须鲶(Ageneiosus marmoratus)全基因组微卫星分布特征研究

根据NCBI已公布的花斑无须鲶全基因组序列,利用MISA软件对花斑无须鲶全基因组的6种完整型微卫星进行筛选并分析其分布特征. 结果如下:在花斑无须鲶全基因组(约1.03Gb)中符合条件的微卫星序列共336 037个,丰度为326个/Mb. 微卫星总长度为7 720 686 bp,占花斑无须鲶全基因组的0.75%. 其中二碱基类型的微卫星数目最多,为145 318个,占微卫星总数的43.24%,其次分别为单碱基(37.12%)、三碱基(11.00%)、四碱基(7.39%)、五碱基(1.04%)和六碱基(0.21%). 花斑无须鲶全基因组微卫星中的优势碱基类别按照数量从高到低排列依次为A、AC、AG、AT、AAT、AAAT、TATC、AAG、AAC和TGA,共有305 243个,占微卫星总数的 90.84%,A、T碱基在微卫星中占绝对优势.